Vacuum lifting device,preferably for flat objects



March 4, 1969 M 3,431,010

VACUUM LIFTING DEVICE, PREFERABLY FOR FLAT OBJECTS Filed Sept. 6, 1967 Sheet of 2 In v en [or Ru do// G/anemann QFWQ March 4, 1969 R. GLANEMANN 3,431,010

VACUUM LIFTING DEVICE, PREFERA'BLY FOR FLAT OBJECTS Filed Sept. 6, 1967 I Sheet Z of 2 Fig.)

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Audo/f Glanemann United States Patent 48,369 U.S. c1. 294-64 7 ClallIlS Int. Cl. B66c 1/02 ABSTRACT OF THE DISCLOSURE A vacuum lifting device, preferably for flat objects, is provided, wherein an outer cylinder, adapted to be placed on an object to be lifted, has in its interior a piston and thereabove an inner cylinder of a diameter leaving an annular chamber between both cylinders into which a U-shaped flexible sheet gasket extends from above. A cover provided with a non-return valve and an air discharge valve closes the annular chamber on top. The piston has a geared down piston rod in the lower end of which a reversing valve including an operating cylinder is provided which automatically opens and closes.

Background of the invention This invention relates to vacuum lifting devices, and more specifically to a vacuum lifting device in which the load to be lifted itself produces a vacuum by means of a cylinder-piston arrangement.

Summary of the invention It is the object of the present invention to provide an automatically reversing vacuum lifting device which despite small measurements and a relatively low weight is very eflicient in operation and further shows special safety arrangements.

To attain this object the present invention provides a vacuum lifting device, preferably for flat objects, which comprises an outer cylinder, a holding ring and a sealing ring surrounding the lower circumference of said outer cylinder, an inner cylinder of a length shorter than that of the outer cylinder and arranged in the upper part of the latter so as to leave an annular chamber between itself and the upper wall portion of the outer cylinder, an annular cover for sealing said annular chamber on top, a piston arranged in the lower part of the outer cylinder and open on top and having a cylindrical wall adapted to be pushed into the annular chamber from below, and a movable sheet gasket secured to the upper end of the cylindrical wall of the piston to seal the annular chamber from below.

Brief description of the drawings FIG. 1 is an axial section through one embodiment of the vacuum lifting device according to the invention;

FIG. 2 is a front view, on an enlarged scale, of the automatic reversing valve;

FIG. 3 is a cross section through the automatic reversing valve on the line III-III of FIG. 2, and

FIG. 4 is a projection of the toothings of the automatic reversing valve.

Description of the preferred embodiment As shown in FIG. 1, a holding ring 11 is secured to an outer cylinder and supports a sealing ring 12 with a support 13 of semi-circular cross section. The outer ice cylinder 10 and a relatively short inner cylinder 14 form an annular chamber 16 in the upper part of the outer cylinder 10. The annular chamber 16 is closed on top by an annular cover 15. A piston 17 open on top is arranged in the lower part of the outer cylinder 10 and has a cylindrical wall 18 adapted to be pushed into the annular chamber 16 from below. To the free end of the piston wall 18 a movable sheet gasket is secured to seal the annular chamber 16 from below.

The movable sheet gasket closing the annular chamber 16 on the piston side is preferably constructed as a flexible roller sheet gasket 19 which is screwed fast, on the one hand, between the annular cover 15 and an external flange 20 on the outer cylinder 10 respectively an inner flange 21 on the inner cylinder 14 and, on the other hand, between a fastening ring 22 and an inner flange 23 provided on the free end of the piston wall 18.

The roller sheet gasket 19 is preferably of U-shaped cross section and lies loosely against the inner upper wall portion of the outer cylinder 10 and the outer wall of the inner cylinder 14.

To the lower part of the inner cylinder 14 a plate 24 with a large borehole is fixed, on which plate, adjacent the borehole, a guide ring 25 for a guide cylinder 26 extending through the borehole in the plate 24 and fastened to the base of the piston 17 is mounted. Through an axial bore in the guide cylinder 26 a simple or multiple geared down piston rod 27 is passed which is capable of being moved to a small extent upwards and downwards and which has, at its end nearest to the piston base, an external collar 28.

To the base of the piston 17 and inside the guide cylinder 26 there is secured a base ring 30 showing an internal collar 29 which has some clearance from the base. In the resulting space the external collar 28 at the end of the piston rod 27 is rotatable and can be raised and lowered between the piston base and the internal collar 29 of the base ring 30.

On both sides of the piston rod end remote from the piston two cover plates 31 are arranged parallel to each other and equipped with guiding rollers 32 between them. Chains 33 pass around the guiding rollers 32 and are respectively connected to one of supporting arms 34 on the annular cover 15 and to a load-ring 35 provided above the piston rod 27.

The roller sheet gasket 19 of flexible material preferably continues from the internal flange 21 of the inner cylinder 14 and, by means of a concentric cut-out portion, is pushed over the piston rod 27 up to the guide cylinder 26.

The annular cover 15 shows two boreholes in which a non-return valve 36, blocking the outlet, and an air discharge valve 37 with a whistle is secured. Under the air discharge valve 37 and in the extension of its borehole in the annular cover 15 a valve tappet is provided which when activated by the piston 17, i.e. by the fastening ring 22, opens the air discharge valve 37 so that the compressed air can escape through the whistle thereby causing a warning signal. Further a manometer 44 is foreseen.

The automatically working reversing .valve consists of a short toothed sleeve 38 engaging deeply into an axial borehole provided in the piston rod 27. Under this short toothed sleeve 38, likewise pressed intothe borehole, there is provided a long toothed sleeve 39, The toothings 40 of the sleeves 38 and 39 are arranged "to lie opposite each other, with the teeth being somewhat out of alignment. The teeth of the lower long toothed sleeve 39 have alternately varying tooth depths. All teeth have a slope of 45.

FIGS. 2 and 3 show an operating cylinder 41 which carries a steel pin 42 and is turnable and capable of being moved vertically in the long toothed sleeve 39. This steel pin 42 is dimensioned so as to project on both sides beyond the outer surface of the operating cylinder 41. While the long toothed sleeve 39 disappears entirely in the piston rod 27, the operating cylinder 41 projects a little therefrom. In the lower end of the operating cylinder 41 a valve disc 43 having a rubber packing is provided.

Finally several air discharge boreholes 45 and '46 are provided through which, following the placing of the lifting device on the object to -be lifted, on the lowering of the piston 17 the displaced air can escape. Such boreholes 45 and 46 are provided radial in the base ring 30 and the guide cylinder 26, further axially in the plate 24 and likewise again radial and at several points in the piston rod 27.

The lifting device proposed by the invention operates as follows:

Due to the reduced drive ratio the attachment of a load results in a double strength of pull on the piston rod 27 and produces a vacuum which is twice as powerful as that produced up to now by the known lifting devices using vacuum. By the created forces the wall 18 of the piston 17 is moved upwards into the annular chamber 16. By the provision of the flexible roller sheet gasket 19, which provides a complete air seal, a high pressure forms in the annular chamber 16. Where the leaks occur, e.g. in the article picked up, air enters from outside the vacuum produced which results in that the piston wall 18 moves further upwards in the annular chamber 16. When the valve tappet of the air discharge valve 37 is activated by the fastening ring 22 of the upwardly moving piston 17 a warning signal is given through the whistle which indicates that no further reserve of lift is available. At this moment however the load is still held by the full vacuum. Only from now on air entering through leaking points causes the vacuum to fall slowly, which one can follow visually by watching the manometer 44. Even on reduction of the vacuum to half value, which corresponds to the maximum vacuum produced by the formerly known lifting devices there is still sufficient time for the release of the load.

The automatic reversing valve operates as follows:

On setting down the lifting device on the fiat surface of an article to be lifted the piston rod 27 is lowered down to the piston base whereby the operating cylinder 41 is forced upwards. The steel pin 42 hereby strikes against teeth of the upper toothing 40. On lifting the piston rod 27, whereby its external collar 28 strikes against the internal collar 29 of the base ring 30 forcing the piston 17 to move upwards, the steel pin 42 slides either in the less deep or the deep slots between each two teeth (FIG. 4). In the one case the valve is opened and the lifting device is lifted without its load and in the other case the valve is closed and vacuum is being produced and the object is carried. By each dropping of the piston rod 27 on to the base of the piston 17 the valve is alternately once opened and once closed. In this manner one can very simply grip a flat object then lay it down, thereupon grip the next object and again lay it down without the necessity of activating any operating or reversing arrangement on the lifting device.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. A vacuum lifting device used preferably for lifting flat objects comprising, in combination:

(a) an outer cylinder,

(b) a holding ring with the sealing ring surrounding the lower circumference of said outer cylinder,

(c) means mounting an inner cylinder of a length shorter than that of the outer cylinder within the upper part of the outer cylinder to form an annular chamber between the inner cylinder and the upper wall portion of the outer cylinder,

(d) an annular cover for sealing said annular chamber on top,

(e) a piston movably mounted in the lower part of the outer cylinder and having an open top portion and a cylindrical wall,

(f) means for moving said cylindrical wall upwardly into the annular chamber from therebelow, and

(g) a movable sheet gasket means secured to the upper end of the cylindrical wall of the piston to seal the annular chamber from the outer cylinder to the inner cylinder.

2. A vacuum lifting device according to claim 1 wherein the movable sheet gasket means secured to the upper end of the cylindrical wall is constructed as a flexible roller sheet gasket which is secured between the annular cover and the outer as well as the inner cylinder to hold the annular chamber from therebelow.

3. A vacuum lifting device according to claim 2, wherein a non-return valve and an air discharge valve with a whistle are secured in boreholes passing through the annular cover.

4. A vacuum lifting device according to claim 1 including a piston rod which is connected to the said piston and carries two guiding rollers on its end away from the piston for the purpose of gear reduction, and chains attached at one end to supporting arms which are fixed to the annular cover are led around the said guiding rollers and attached at the other end to a load ring mounted above the piston rod.

5. A vacuum lifting device according to claim 4 wherein the piston rod has an annular borehole at its end next to the piston and includes an automatically working reversing valve which comprises a short toothed sleeve engaging deeply into the piston rod borehole and a long toothed sleeve arranged below the short toothed sleeve and likewise engaging deeply into the axial borehole of the piston rod, the toothings of the toothed sleeves lying opposite each other with the teeth being somewhat out of alignment.

6. A vacuum lifting device according to claim 5, wherein the teeth of the long toothed sleeve have alternately varying tooth depths.

7. A vacuum lifting device according to claim 5, wherein an operating cylinder is turnable and raisable and lowerable in the long toothed sleeve and through which, in the region of its toothing, a steel pin extends so as to project on both sides beyond its outer surface, and has on its other lower end, fitted into the operating cylinder, a turnable valve disc provided with a sealing disc.

References Cited UNITED STATES PATENTS 3,322,221 5/1967 Engelen 294-64 X FOREIGN PATENTS 163,736 8/1964 U.S.S.R.

ANDRES H. NIELSEN, Primary Examiner. 

